Not all systems
can provide a monotonic clock. How are they expected to
treat a _for function?

Suggestion

Add at least a note explaining the intent
for systems that do not support a monotonic clock.

Notes

Create an issue, together with UK 96. Note that the specification as is
already allows a non-monotonic clock due to the word “should” rather than
“shall”. If this wording is kept, a footnote should be added to make the
meaning clear.

[ 2009-06-29 Beman provided a proposed resolution. ]

[
2009-10-31 Howard adds:
]

Set to Tentatively Ready after 5 positive votes on c++std-lib.

[
2010-02-24 Pete moved to Open:
]

LWG 1158's proposed resolution replaces the ISO-specified normative term
"should" with "are encouraged but not required to", which presumably means the
same thing, but has no ISO normative status. The WD used the latter formulation
in quite a few non-normative places, but only three normative ones. I've changed
all the normative uses to "should".

The member functions whose names end in _for take an argument that
specifies a relative time. Implementations should use a monotonic clock to
measure time for these functions. [Note: Implementations are not
required to use a monotonic clock because such a clock may be unavailable.
— end note]